The use of fiber glass blowing wool or loose-fill insulation is well known and is preferred by many contractors because it can be easily and quickly applied to new and old buildings and is a relatively low cost material. Loose-fill insulation is produced by forming a non-bindered fiber glass mat and grinding the mat up. After applying additives, the fibers are compressed, and packaged into bags. The insulation is installed by adding the loose-fill to the hopper of a pneumatic blower which blows the loose fill insulation into the desired area. The loose fill insulation can be pneumatically applied over large horizontal surfaces, as well as in cavities to which complete access is not available.
Installers of loose-fill insulation have experienced problems in the field due to product aging, collection of static electric charge, and dust. For example, the static electricity problem has been well documented. Often, the distribution of the blowing wool through the application nozzle and air creates a static charge on the fiber surfaces. The static charge is generated during dry or windy weather conditions as the fiberglass material moves through the blowing machine and the hose. These electric charges repel each other causing small fiber particles to spread out causing a “cloud of dust”. Also, static charge causes the fiberglass insulation to stick to the interior surfaces of the attic and the installer, contributes to fiber fly, and can cause a reduction in expected coverage for a given quantity of glass fiber.
In some systems, a hydrophobic agent, such as silicone, was applied to the fiber by spray guns below the spinner, providing uniform coverage. Then the fiber was ground and an antistat was injected onto the fibers. The treated fiber glass material was then ready to be packaged and stored.
Another approach has been to manually add water (alone, or in combination with another liquid such as vegetable oil or anti-freeze) to the hopper by means of a cup or spray bottle. This approach reduces static, but it requires manual intervention by the installer, and may reduce productivity. Also, if excessive water is added, this may reduce the coverage provided by a given quantity (by weight) of insulation.
U.S. Pat. No. 4,555,447, which is incorporated by reference herein, discloses the use of an antistatic agent in the production of blowing wool insulation. The antistat is a quaternary ammonium salt which is applied from an aqueous solution. The antistat reduces the tendency of the small fiber particles to dispense during pneumatic application. When a quaternary ammonium salt antistatic agent was used on the wool, the dust reduction properties were still present six weeks later.
U.S. Pat. No. 5,683,810 further teaches that fabrication of loose-fill insulation product may include the step of applying a dust suppressant or anti-static agent to the surface of the irregularly-shaped fibers before or after the fibers have been cut, milled or chopped.
U.S. Pat. No. 6,732,960, which is incorporated by reference herein, teaches a system for blowing loose-fill insulation, including a loose-fill blowing machine and a discharge hose. An ionizer is disposed in the flow path of the insulation through the discharge hose. The level of static charge is measured or sensed, and the ionizer reduces the static charge developed on the insulation prior to discharge. The insulation is ionized in the flow path of the insulation while the insulation is being discharged to reduce the static charge.
In many cases, the packaged insulation, with the additives applied thereto, was stored more than 90 days after the application of the additives. Additives such as silicone and antistat were not as effective at the end of such a long storage period. As a result, when insulation was kept in storage for periods of 90 days or more, the coverage provided by a package of insulation was less than the coverage provided by the same quantity of insulation if used immediately after manufacture.
An improved method is desired for addressing the static problem in dispensing loose fill insulation.